Prior to the beginning of this grant, we demonstrated that rhodium(II) acetate exhibits potent antitumor activity against Ehrlich ascites tumor carried in Swiss Albino mice. Also when given in combination with arabinosylcytosine to mice implanted with Leukemia 1210 the results are extremely encouraging in that 100 percent cure rates are obtained in some instances. The research proposed involves the synthesis of a wide variety of rhodium(II) carboxylates and the determination of the efficacy of these complexes, alone and in combination with other known anticancer drugs, as anticancer agents. Mechanism of action studies are being carried out with the rhodium(II) complexes in Leukemia 1210 and Ehrlich systems. The research also includes thermodynamic and kinetic studies on the complex formation reactions between the rhodium(II) carboxylates and molecules of biological importance.